title: Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climates.
abstract: Early Cretaceous vertebrate assemblages from East Asia and particularly the Jehol Biota of northeastern China flourished during a period of highly debated climatic history. While the unique characters of these continental faunas have been the subject of various speculations about their biogeographic history, little attention has been paid to their possible climatic causes. Here we address this question using the oxygen isotope composition of apatite phosphate (δ ) from various reptile remains recovered from China, Thailand, and Japan. δ values indicate that cold terrestrial climates prevailed at least in this part of Asia during the Barremian-early Albian interval. Estimated mean air temperatures of about 10 ± 4 °C at midlatitudes (∼ 42 °N) correspond to present day cool temperate climatic conditions. Such low temperatures are in agreement with previous reports of cold marine temperatures during this part of the Early Cretaceous, as well as with the widespread occurrence of the temperate fossil wood genus Xenoxylon and the absence of thermophilic reptiles such as crocodilians in northeastern China. The unique character of the Jehol Biota is thus not only the result of its evolutionary and biogeographical history but is also due to rather cold local climatic conditions linked to the paleolatitudinal position of northeastern China and global icehouse climates that prevailed during this part of the Early Cretaceous.
authors.affiliation: Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi Zhi Men Wai DaJie, Beijing 100044, China. Romain.amiot@univ-lyon1.fr
authors.forename: Romain
authors.initials: R
authors.lastname: Amiot
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Zhonghe
authors.initials: Z
authors.lastname: Zhou
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.forename: Eric
authors.initials: E
authors.lastname: Buffetaut
authors.forename: Christophe
authors.initials: C
authors.lastname: Lécuyer
authors.forename: Zhongli
authors.initials: Z
authors.lastname: Ding
authors.forename: Frédéric
authors.initials: F
authors.lastname: Fluteau
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Hibino
authors.forename: Nao
authors.initials: N
authors.lastname: Kusuhashi
authors.forename: Jinyou
authors.initials: J
authors.lastname: Mo
authors.forename: Varavudh
authors.initials: V
authors.lastname: Suteethorn
authors.forename: Yuanqing
authors.initials: Y
authors.lastname: Wang
authors.forename: Xing
authors.initials: X
authors.lastname: Xu
authors.forename: Fusong
authors.initials: F
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001031:Apatites / Q000737:chemistry; D001208:Asia; D005075:Biological Evolution; D003081:Cold Climate; D025061:Dinosaurs / Q000033:anatomy & histology; D005580:Fossils; D010103:Oxygen Isotopes / Q000032:analysis*; D010710:Phosphates / Q000737:chemistry
chemical_list: D001031:Apatites; D010103:Oxygen Isotopes; D010710:Phosphates